The present invention relates to a pressure regulating device and in particular to a pressure regulating device for pressure fluid-operable brake systems used in automotive vehicles.
Pressure regulating devices of this type are primarily provided for the regulation of brake pressure to the rear wheels and are arranged between the master cylinder and rear wheel brake of the vehicle to bring the distribution of the brake forces on the front and rear axles during deceleration closer to an ideal distribution characteristic.
A pressure regulating device of this type is disclosed in the German publication DE-OS No. 31 00 916 A1. In the pressure regulator disclosed therein, the input pressure is applied to the regulating piston through a spring and an intermediate piston. The connection between the pressure fluid inlet and the intermediate piston, is interrupted by an inertia element during a predetermined deceleration condition. Upon interruption of the connection, the regulating piston is displaced against the force of the afore-mentioned spring, whereas the intermediate piston, the cross-sectional surface area of which exceeds that of the regulating piston, maintains its position.
This prior art pressure regulator has the disadvantage that the characteristic of the pressure pattern is static after the connection between the pressure fluid inlet and the intermediate piston has been closed by the inertia element.